Holding assembly for cross-connected optical fibers between plural fiber ribbons

ABSTRACT

A ribbon holder is provided for a plurality of fiber optic ribbons. The holder includes a body having an interior rectangular through passage in which the plurality of fiber optic ribbons can be placed in a side-by-side parallel arrangement. A cover is provided on the body to allow access to the through passage whereby the ribbons can be placed into the passage thereof. An exterior datum surface is provided at one side of the body to identify one side of the interior rectangular through passage, whereby the ribbons can be placed in the passage in specific orientations relative to said datum surface.

FIELD OF THE INVENTION

This invention generally relates to the art of optical fibers and,particularly, to a holding assembly for use in a system ofcross-connecting or reorganizing the individual optical fibers of aplurality of fiber optic ribbons.

BACKGROUND OF THE INVENTION

Fiber optic circuitry is increasingly being used in electronics systemswhere circuit density is ever-increasing and is difficult to providewith known electrically wired circuitry. An optical fiber circuit isformed by a plurality of optical fibers carried by a dielectric, and theends of the fibers are interconnected to various forms of connectors orother optical transmission devices. A fiber optic circuit may range froma simple cable which includes a plurality of optical fibers surroundedby an outer cladding or tubular dielectric to a more sophisticatedoptical backplane or flat fiber optic circuit formed by a plurality ofoptical fibers mounted on a substrate in a given pattern or circuitgeometry.

One type of optical fiber circuit is produced in a ribbonizedconfiguration wherein a row of optical fibers are disposed in aside-by-side parallel array and coated with a matrix to hold the fibersin the ribbonized configuration. In the United States, a twelve-fiberribbon has fairly become the standard. In other foreign countries, thestandard may range from as a low as four to as high as twenty-fourfibers per ribbon. Multi-fibers ribbons and connectors have a wide rangeof applications in fiber optic communication systems. For instance,optical splitters, optical switches, routers, combiners and othersystems have input fiber optic ribbons and output fiber optic ribbons.

With various applications such as those described above, the individualoptical fibers of input fiber optic ribbons and output fiber opticribbons are cross-connected or reorganized whereby the individualoptical fibers of a single input ribbon may be separated and reorganizedinto multiple or different output ribbons. The individual optical fibersare cross-connected or reorganized in what has been called a “mixingzone” between the input and output ribbons. The present invention isdirected to various improvements in this concept of cross-connecting orreorganizing the individual optical fibers of a plurality of input andoutput ribbons.

SUMMARY OF THE INVENTION

An object, therefore, of the invention is to provide a new and improvedholding assembly for cross-connected or reorganized optical fibers of aplurality of fiber optic ribbons, wherein a plurality of input ribbonslead to an input end of a reorganizing section of loose fibers, and witha plurality of output ribbons leading from an output end of thereorganizing section.

In the exemplary embodiment of the invention, the holding assemblyincludes a sleeve element surrounding the loose fibers at thereorganizing section. A ribbon holder is disposed at least at one end ofthe sleeve element. The ribbon holder has an interior rectangularthrough passage in which a plurality of ribbons can be placed in aside-by-side parallel arrangement. An exterior datum means is providedat one side of the ribbon holder to identify one side of the interiorrectangular through passage, whereby the ribbons can be placed in theribbon holder in specific orientations relative to the datum means.

As disclosed herein, the ribbon holder includes a cover to allow accessto the through passage whereby the ribbons can be placed into thepassage transversely thereof. The cover is hinged to the ribbon holder.Preferably, the ribbon holder is molded of plastic material, with thecover being molded integrally therewith by a living hinge.

According to an aspect of the invention, the datum means is formed by aflat surface on the exterior of the ribbon holder. The exterior flatsurface is generally parallel to the one side of the interiorrectangular through passage. The exterior of the ribbon holder isgenerally cylindrical except for the flat surface.

Other features of the invention include retaining means to hold theribbon holder at the one end of the sleeve element. As disclosed herein,the ribbon holder is disposed within the one end of the sleeve element,and gripping means are provided on the outside of the sleeve element toclamp the sleeve element onto the ribbon holder. In the preferredembodiment, one of the ribbon holders are provided at each opposite endof the sleeve element for both the input and output ribbons.

Other objects, features and advantages of the invention will be apparentfrom the following detailed description taken in connection with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of this invention which are believed to be novel are setforth with particularity in the appended claims. The invention, togetherwith its objects and the advantages thereof, may be best understood byreference to the following description taken in conjunction with theaccompanying drawings, in which like reference numerals identify likeelements in the figures and in which:

FIG. 1 is a plan view of a cross-connected optical fiber harnessaccording to the invention;

FIG. 2 is an enlarged axial section through the ribbon holding assemblytaken generally along line 2—2 of FIG. 1;

FIG. 3 is an enlarged section through the left-hand ribbon holder of theassembly, taken generally along line 3—3 of FIG. 1;

FIG. 4 is a view similar to that of FIG. 3, but of the right-hand ribbonholder, taken generally along line 4—4 of FIG. 1;

FIG. 5 is a side elevational view of one of the ribbon holders;

FIG. 6 is an end elevational view of the ribbon holder in closedcondition and holding twelve ribbons therewithin;

FIG. 7 is a section taken transversely through the ribbon holder in itsopen position;

FIG. 8 is a view of the cross-connected optical fiber harness of FIG. 1,with the fiber optic ribbons terminated to a plurality of connectors;

FIG. 9 is a plan view of a substrate on which a plurality of fiber opticribbons have been cross-connected or reorganized by a mechanical routingapparatus; and

FIG. 10 is an elevational view of the routing head of the routingapparatus.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings in greater detail, and first to FIG. 1, across-connected optical fiber harness, generally designated 12, is shownfabricated according to the invention. Basically, the harness isinvolved in a system for cross-connecting or reorganizing the individualoptical fibers of a plurality of fiber optic ribbons. In FIG. 1, aplurality (six) of input ribbons 14 lead to an input end, generallydesignated 16, of a reorganizing section 18. Although not visible inFIG. 1, the fibers in the reorganizing section are maintained loose. Aplurality (eight) of output ribbons 20 lead away from an output end,generally designated 24, of the reorganizing section. In thereorganizing section, the individual optical fibers from any given inputribbon 14 may be cross-connected into more than one output ribbon 20.Once all of the individual fibers of the input ribbons are reorganizedand cross-connected into the output ribbons, a ribbon holding assembly,generally designated 26, is positioned about the loose fibers in thereorganizing section and clamping the input and output ribbons atopposite ends of the reorganizing section.

FIG. 2 shows a longitudinal section through ribbon holding assembly 26to show the various components thereof. Specifically, a pair of ribbonholders, generally designated 28A and 28B, are disposed at opposite endsof the assembly and clamp onto the ribbons as will be described ingreater detail hereinafter. A sleeve 30, such as of fiberglass material,extends between ribbon holders 28A and 28B spanning reorganizing section18, and within which loose individual optical fibers 32 cross-connectedbetween the input and output ribbons are protected. The fiberglasssleeve may be split lengthwise to facilitate positioning the sleevearound the loose fibers and around ribbon holders 28A and 28B. A pair ofthermally shrinkable tubes 34 are positioned about opposite ends ofsleeve 30 to surround ribbon holders 28A and 28B. The shrinkable tubesare shrunk in response to heat to clamp sleeve 30 onto the ribbonholders. Finally, for identification purposes, a cylindrical label 36may be placed about sleeve 30.

FIGS. 3 and 4 show left-hand ribbon holder 28A and right-hand ribbonholder 28B as viewed in FIG. 1, surrounded by fiberglass sleeve 30 andshrink tubes 34. Each ribbon holder defines a rectangular or squarethrough passage 38 for receiving the fiber optic ribbons. As statedabove in relation to FIG. 1, six input ribbons 14 enter reorganizingsection 18 and eight output ribbons 20 leave the reorganizing section.Therefore, ribbon holder 28A (FIG. 3) holds the six input ribbons 14,and ribbon holder 28B (FIG. 4) holds the eight output ribbons 20. Inorder accommodate the different numbers of ribbons within passages 38and to maintain the ribbons in side-by-side parallel arrays, fillerelements 40 are placed at opposite sides of the “bundle” of ribbons tocompletely fill the passages. These filler elements may be of a varietyof materials, but sections of foam tape have proven effective.

Before proceeding with the details of ribbon holders 28A and 28B inFIGS. 5-7, reference is made back to FIG. 1. It can be seen that inputribbons 14 have been identified with labels 42 having the indicia“P1-P6” to identify the six input ribbons. Similarly, output ribbons 20have been identified with labels 42 having the indicia “A1-A8”corresponding to the eight output ribbons. Optical fiber harness 12 isused in a particular overall circuit scheme wherein it is desirable forinput ribbons 14 to be maintained in a given sequence, and it isparticularly important for output ribbons 20 to leave reorganizingsection 18 in a particular sequence. For instance, output ribbons 20 maybe connected at various physical locations in a backplane system and itis not desirable to have the ribbons twisted back and forth over eachother in order to connect the ribbons. It can be seen that input ribbons14 are maintained by ribbon holding assembly 26 in a given sequence(top-to-bottom) P2-P1-P5-P6-P3-P4 in order to conveniently arrange theinput ribbons according to the circuit scheme. Similarly, output ribbons20 are arranged top-to-bottom A1-A5-A2-A6-A3-A7-A4-A8. Ribbon holdingassembly 26 allows easy maintenance of this or any other particularsequential arrangement of the ribbons.

In addition, and still referring to FIG. 1, as pointed out in the“Background”, above, each fiber optic ribbon has twelve individualoptical fibers as represented by “1-12” in the drawings. It is importantthat an operator be able to know which tiny individual fiber of eachribbon is the “1” or the “12” fiber within the ribbon, and ribbonholding assembly 26, particularly ribbon holders 28A or 28B, allow forthis important organization.

With that understanding, reference is made to FIGS. 5-7 in conjunctionwith FIGS. 3 and 4. It should be noted that ribbon holder 28 in FIG. 6contains twelve fiber optic ribbons “R”. This is for illustrationpurposes only to show that the holder is capable of holding that manyribbons, versus ribbon holder 28A (FIG. 3) and ribbon holder 28B (FIG.4) which hold six and eight ribbons, respectively. In other words,ribbon holder 28 in FIG. 6 does not need to have any filler elements 40(FIGS. 3 and 4), because the twelve ribbons completely fill throughpassage 38.

As best seen in FIGS. 5-7, ribbon holder 28 includes a body 44 and acover 46 which combine in their closed position of FIG. 6 to forminterior rectangular through passage 38. The entire ribbon holder may befabricated in one piece of molded plastic material, for instance. Cover46 is attached to body 44 by an integral living hinge 48 formed duringthe molding process. The cover includes a latch boss 50, and the bodyincludes a latch recess 52 for receiving the latch boss to hold thecover in a closed position about ribbons “R” as seen in FIG. 6. Thecover can be opened as seen in FIG. 7 to allow access to through passage38 whereby the ribbons can be placed into the passage transverselythereof. The exterior of body 44 and cover 46 are molded with serrationsor circumferential ribs 54 which help sleeve 30 (FIGS. 3 and 4) andshrink tubes 34 to grip the ribbon holders.

Generally, an exterior datum means is provided at one side of the ribbonholder to identify one side of the interior rectangular through passage38, whereby ribbons “R” can be placed in the holder in specificorientations relative to the datum means. Specifically, the datum meansof ribbon holder 28 is provided by a flat surface 56 molded on theexterior of body 44 generally parallel to one side 38 a of rectangularthrough passage 38. In essence, flat surface 56 defines a datum planegenerally parallel to side 38 a of the through passage.

With the provision of flat surface or datum plane 56, reference is madeto FIG. 6 wherein the top individual optical fibers of all of theplurality of fiber optic ribbons “R” are identified as #1. It can beseen that all of the #1 fibers are juxtaposed against interior side 38 aof through passage 38, with the #12 fibers of all of the ribbons locatedagainst the opposite interior side or wall of the through passage. Withflat surface 56 being parallel to and at the same side as interior wall38 a of the through passage, an operator knows the location of all ofthe #1 individual optical fibers of all of the ribbons inside the ribbonholder simply by looking at the outside of the holder. In fact, flatsurface 56 not only gives a visual indication of the location of theindividual fibers but a tactile indication as well.

FIG. 8 simply shows the cross-connected optical fiber harness 12 of FIG.1 fully terminated in a harness/connector assembly. Specifically, inputribbons 14 are terminated to a plurality of fiber optic connectors 60.Output ribbons 20 are terminated to a plurality of fiber opticconnectors 62.

FIGS. 9 and 10 show a unique method of cross-connecting or reorganizingthe individual optical fibers of a plurality of fiber optic ribbons andmay be used to form the cross-connected optical fiber harness of FIG. 1.Specifically, FIG. 9 shows a substrate 64 having an adhesive thereon. Amixing zone 66 is defined within the boundaries of the substrate. Forexplanation purposes, the mixing zone has an input side 66 a and anoutput side 66 b. Actually, a smaller substrate 68 is adhered to largersubstrate 64 and encompasses the mixing zone. The smaller substrate alsohas an adhesive thereon. The invention contemplates using a mechanicalrouting apparatus (described hereinafter) for routing a plurality ofindividual optical fibers 32 onto substrates 64 and 68 to form aplurality of fiber optic input ribbons 14 leading to input side 66 a ofmixing zone 66, reorganizing the individual fibers in the mixing zone,and forming a plurality of fiber optic output ribbons 20 leading awayfrom output side 66 b of the mixing zone. In other words, input ribbons14 and output ribbons 20 correspond to the input and output ribbonsdescribed above in relation to the cross-connected optical fiber harness12 of FIG. 1. For illustrative purpose, only three input ribbons andfour output ribbons are shown. Of course, two of such arrangements, asshown in FIG. 9, could be combined to make the arrangement as shown inFIG. 1.

In order to understand the reorganizing or mixing of individuals fibers32 in mixing zone 66 between input ribbons 14 and output ribbons 20, theinput ribbons have been labeled 14 a-c and the output ribbons have beenlabeled 20 a-20 d. It can be seen that there are three input ribbons andfour output ribbons. It also can be seen in FIG. 9 that four fibers 32from input ribbon 14 a and six fibers from input ribbons 14 b are mixedor combined to form output ribbon 20 b. Six individual optical fibers 32from each of input ribbons 14 b and three fibers 32 from input ribbon 14c are mixed or combined to form output ribbon 20 c. Eight individualoptical fibers from input ribbon 14 a and eight fibers from input ribbon14 c form output ribbons 20 a and 20 d, respectively. All of thesefibers are mechanically routed onto substrates 64 and 68 by a mechanicalrouting apparatus, generally designated 70 in FIG. 10, which includes arouting head 72. The apparatus including the routing head can pivotabout an axis 74 as it moves in the direction of arrow 76. An individualoptical fiber 32A is fed into a funnel 78 of the apparatus and is fed toa needle 80 which applies the fiber to substrates 64 and 68, whereby thefibers are held onto the substrates by the adhesive material on thesubstrates. The apparatus includes a cut-off mechanism as is known inthe art. Further details of such a routing apparatus can be derived fromcopending application Ser. No. 09/645,624, filed Aug. 24, 2000, assignedto the assignee of the present invention, and which is incorporatedherein by reference. Lastly, for purposes described hereinafter, some ofthe individual fibers of output ribbons 20 are cut-off as at 82 (FIG. 9)before entering mixing zone 66.

After the fibers are mechanically routed onto substrates 64 and 68 asseen in FIG. 9, input and output ribbons 14 and 20, respectively, arecoated with a curable plastic material on the substrates at leastoutside mixing zone 66 to hold the routed fibers in ribbon form. Thecoating may cover the fibers over opposite ends of smaller substrate 68up to input and output sides 66 a and 66 b, respectively, of the mixingzone.

After fiber optic ribbons 14 and 20 are coated and the coating is curedto hold the fibers in ribbonized form, the coated fibers are strippedfrom substrates 64 and 68 so that ribbon holding assembly 26 (FIGS. 1and 2) can be assembled over the loose fibers between the input andoutput ribbons thereof. In other words, individual optical fibers 32that were within mixing zone 66 were uncoated and, therefore, remainloose as seen in FIG. 2. Otherwise, ribbon holding assembly 26 isinstalled over the ribbons and loose fibers as described above inrelation to FIGS. 1-7. Labels 42 (FIG. 1) and/or connectors 60/62 (FIG.8) may be applied or terminated to the fiber optic ribbons.

The reason that smaller substrate 68 is installed on top of largersubstrate 64 is to provide a subassembly which can be stored prior toinstalling ribbon holding assembly 26. In other words, the coated andcured input and output ribbons 14 and 20, respectively, may be strippedfrom larger substrate 64 and still be adhered to smaller substrate 68outside the bounds of mixing zone 66. This subassembly of substrate 68and the cross-connected and ribbonized ribbons may then be shipped toanother processing station or stored in inventory before installingribbon holding assembly 26. During the transport or storing of thesubassembly, loose individual optical fibers 32 still remain adhesivelysecured to smaller substrate 68 and the ribbons, themselves, aremaintained manageable for subsequent installation of ribbon holdingassembly 26. Substrate 68 is removed for installation of ribbon holdingassembly 26.

Finally, as stated above, some of the individual optical fibers ofoutput ribbons 20 are cut-off, as at 82 in FIG. 9, before extending intomixing zone 66. This is easily accomplished with mechanical routingapparatus, but it would be extremely difficult if the tiny individualfibers are routed or otherwise handled by manual manipulation. Byrouting twelve fibers in each input ribbon and cutting the individualfibers off even though they are not cross-connected into output ribbons20, input ribbons 14 are maintained with twelve fibers in each ribbon.The cut-off of course could also be done on the input side. If referenceis made back to FIG. 6, it can be understood that by keeping twelvefibers in each ribbon, the ribbons will fill the space within passage 38of ribbon holder 28 between inside wall 38 a and the opposite wall ofthe passage.

Additionally, the cut-off fibers, also known as dummy fibers, aredesigned into fiber routing scheme because of the ease of installationof twelve fiber ribbons into twelve channel connector ferrules.

It will be understood that the invention may be embodied in otherspecific forms without departing from the spirit or centralcharacteristics thereof. The present examples and embodiments,therefore, are to be considered in all respects as illustrative and notrestrictive, and the invention is not to be limited to the details givenherein.

What is claimed is:
 1. In a system for cross-connecting or reorganizingindividual optical fibers of a plurality of fiber optic ribbons, whereina plurality of input ribbons lead to an input end of a reorganizingsection of loose fibers and with a plurality of output ribbons leadingfrom an output end of the reorganizing section, a holding assembly,comprising: a sleeve element surrounding the loose fibers at saidreorganizing section; and a ribbon holder at least at one end of thesleeve element, the ribbon holder including an interior rectangularthrough passage in which said plurality of ribbons can be placed in aside-by-side parallel arrangement, and an exterior datum means visiblefrom an exterior of the ribbon holder at one side thereof to identifyone side of the interior rectangular through passage whereby the ribbonscan be placed in the ribbon holder in specific orientations relative tosaid datum means.
 2. The holding assembly of claim 1, including oneribbon holder at each opposite end of the sleeve element for both theinput and output ribbons.
 3. The holding assembly of claim 1, includingretaining means to hold the ribbon holder at said one end of the sleeveelement.
 4. The holding assembly of claim 1 wherein said ribbon holderis disposed within said one end of the sleeve element.
 5. The holdingassembly of claim 4, including gripping means on the outside of thesleeve element at said one end thereof to clamp the sleeve element ontothe ribbon holder.
 6. The holding assembly of claim 1 wherein saidribbon holder includes a cover to allow access to the through passagewhereby the ribbons can be placed into the passage transversely thereof.7. The holding assembly of claim 6 wherein said cover is hinged to theribbon holder.
 8. The holding assembly of claim 7 wherein said ribbonholder is molded of plastic material with said cover being moldedintegrally therewith by a living hinge.
 9. The holding assembly of claim1 wherein said datum means comprises a flat surface on an exterior ofthe ribbon holder.
 10. The holding assembly of claim 9 wherein saidexterior flat surface is generally parallel to said one side of theinterior rectangular through passage.
 11. The holding assembly of claim10 wherein the exterior of said ribbon holder is generally cylindricalexcept for said flat surface.
 12. In a system for cross-connecting orreorganizing individual optical fibers of a plurality of fiber opticribbons, wherein a plurality of input ribbons lead to an input end of areorganizing section of loose fibers and with a plurality of outputribbons leading from an output end of the reorganizing section, aholding assembly, comprising: a sleeve element surrounding the loosefibers at said reorganizing section; and a pair of ribbon holdersdisposed at opposite ends of the sleeve element, each ribbon holderincluding an interior rectangular through passage in which a respectiveone of said plurality of input ribbons and plurality of output ribbonscan be placed in a side-by-side parallel arrangement, a cover associatedwith each ribbon holder to allow access to the through passage thereofwhereby the ribbons can be placed into the passage transversely thereof,and a flat datum surface on an exterior of each ribbon holder generallyparallel to one side of the interior rectangular through passage andvisible from the exterior of the ribbon holder to identify said one sidewhereby the ribbons can be placed in the ribbon holder in specificorientations relative to said flat datum surface.
 13. The holdingassembly of claim 12, including retaining means to hold the ribbonholders at opposite ends of the sleeve element.
 14. The holding assemblyof claim 12 wherein said ribbon holders are disposed within oppositeends of the sleeve element.
 15. The holding assembly of claim 14,including gripping means on the outside of the sleeve element at theopposite ends thereof to clamp the sleeve element onto the ribbonholders.
 16. The holding assembly of claim 12 wherein said cover of eachribbon holder is hinged to the respective ribbon holder.
 17. The holdingassembly of claim 16 wherein said ribbon holders are molded of plasticmaterial with the covers being molded integrally therewith by livinghinges.
 18. The holding assembly of claim 12 wherein the exterior ofsaid ribbon holders are generally cylindrical except for said flat datumsurfaces.
 19. A ribbon holder for a plurality of fiber optic ribbons,comprising: a body having an interior rectangular through passage inwhich the plurality of fiber optic ribbons can be placed in aside-by-side parallel arrangement; a cover on the body to allow accessto the through passage whereby the ribbons can be placed into thepassage transversely thereof and an exterior datum means visible from anexterior of the body at one side thereof to identify one side of theinterior rectangular through passage whereby the ribbons can be placedin the passage in specific orientations relative to said datum means.20. The ribbon holder of claim 19 wherein said cover is hinged to thebody.
 21. The ribbon holder of claim 20 wherein said body is molded ofplastic material with said cover being molded integrally therewith by aliving hinge.
 22. The ribbon holder of claim 19 wherein said datum meanscomprises a flat surface on the exterior of the body.
 23. The ribbonholder of claim 22 wherein said exterior flat surface is generallyparallel to said one side of the interior rectangular through passage.24. The ribbon holder of claim 23 wherein the exterior of said body isgenerally cylindrical except for said flat surface.
 25. A ribbon holderfor a plurality of fiber optic ribbons, comprising: a body having aninterior rectangular through passage in which the plurality of fiberoptic ribbons can be placed in a side-by-side parallel arrangement; andan exterior datum means visible from an exterior of the body at one sidethereof to identify one side of the interior rectangular through passagewhereby the ribbons can be placed in the passage in specificorientations relative to said datum means.
 26. The ribbon holder ofclaim 25 wherein said datum means comprises a flat surface on theexterior of the body.
 27. The ribbon holder of claim 26 wherein saidexterior flat surface is generally parallel to said one side of theinterior rectangular through passage.
 28. The ribbon holder of claim 27wherein the exterior of said body is generally cylindrical except forsaid flat surface.